CENTER FOR TRANSGENIC ANIMALS AND PLANTS

I. Research supporting activity

NIBB Center for Transgenic Animals and Plants was established in April 1998 to support researches using transgenic and gene targeting techniques in NIBB. We are now planning on the construction of the center building.

The expected activities of the Center are as follows:

1. Provision of information, materials and techniques to researchers.
2. Equipment of various instruments to analyze mutant animals and plants.
3. Development of novel techniques related to transgenic and gene targeting technology.

II. Academic activity

We are studying the functional role of Na_x sodium channel in collaboration with Division of Molecular Neurobiology. Na_x has belonged to a subfamily of voltage-gated sodium channels (NaChs) that serve to generate action potentials in electrically excitable cells such as neuronal and muscle cells. Comparing with the other NaChs, Na_x has unique amino acid sequences in the regions, which are known to be involved in ion selectivity and voltage-dependent activation and inactivation, suggesting that it must have specific functional properties. To clarify the functional role Na_xin vivo, the Na_x-deficient mice were generated by gene targeting and the physiological phenotypes have been examined. It was suggested that the Na_x channel plays an important role in the central sensing of body-fluid sodium level and regulation of salt intake behavior. Details of this study are described in the part of Division of Molecular Neurobiology.

Fig. 1 Nax sodium channel is a candidate molecule for the sodium-level sensor in the brain. The schematic representation indicates a sagittal plane of the mouse brain at midline level. The boxed regions are the circumventricular organs, which are tissues situated outside of the blood-brain barrier and surrounded the ventricle of brain, and a site convenient for monitoring the levels of various substances in both plasma and CSF. Nax sodium channel is expressed in specialized neurons and ependymal cells of the circumventricular organs as shown in red. We also found abnormal salt ingestion in the Nax-deficient mice.

Publication List

Zubair, M., Watanabe, E., Fukada, M. and Noda, M. (2002) Genetic labeling of specific axonal pathways in the mouse central nervous system. Eur J Neurosci, in press.